The invention provides an arc extinguishing chamber contact compression spring assembling process and assembling tool. During assembling, rotation of an arc extinguishing chamber is restrained in thecircumferential direction to determine the position of a static threaded hole of the arc extinguishing chamber, a spring cylinder is fixedly assembled with a movable contact rod of the arc extinguishing chamber, a contact compression spring and a pull rod joint are inserted in the spring cylinder, the orientation of a pull rod joint pin hole is aligned to make the positional relationship between the pull rod joint pin hole and the static end threaded hole of the arc extinguishing chamber in the circumferential direction of the arc extinguishing chamber satisfy design and assembly requirements;the contact compression spring is driven to compress and deform through pressing the pull rod joint, a fixed stop member in stop matching with the pull rod joint is fixedly assembled on the spring cylinder to limit the contact compression spring to the maximum release stroke, and contact compression spring assembling is completed. The contact compression spring can be easily compressed throughoutthe assembling process, and that the pull rod point pin hole and the static threaded hole have the qualified positional relationship is guaranteed.